Magnetic Properties, Self-Temperature Rising Characteristics, and Biocompatibility of NiFe$_2$O$_4$Nanoparticles for Hyperthermia Applications

This paper reports first on the very promising self-heating and temperature rising characteristics of solid-state NiFe
$_2$
O
$_4$
nanoparticles for hyperthermia applications. NiFe
$_2$
O
$_4$
nanoparticles were prepared by using both the “high temperature thermal decomposition method (HTTD)” and the “newly modified sol-gel” methods. The magnetic properties and cell-cytotoxic properties of the synthesized NiFe
$_2$
O
$_4$
nanoparticles were investigated to consider these nanoparticles for in vivo hyperthermia applications. The saturation magnetic moments measured by a high sensitive SQUID were between 43.0 and 47.6 emu/g. The cell survival rates of NiFe
$_2$
O
$_4$
and chitosan coated NiFe
$_2$
O
$_4$
, which were determined by MTT assay, around 85 % and 98.8 %, respectively. The maximum self-heating temperature induced by our specially designed RF-MRI modified L-C circuit was 47.3
$^circ$
C and the frequency and magnetic field product,
$H_0f$
was 1.07
$times$
10
$^9$
Am
$^-1$
s
$^-1$
.